Libusbdotnet HID Read (Event Driven) Error - hid

Question

I used LibUSbDotNet for read USB data from my Hardware using Event Driven operation. My hardware pumps out data at two different intervals. (2000 ms and 300 ms). The buffer size is 7 bytes.
The code works fine for sometimes afterwards the reading is slowed. instead of 2000 and 300 ms the data receives at 4000 and 2000 ms.
Please help me resolve this issue guys...
regards
John
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using LibUsbDotNet;
using LibUsbDotNet.DeviceNotify;
using LibUsbDotNet.Main;
namespace ATE_BackEnd
{
public partial class Main_Form : Form
{
public static IDeviceNotifier UsbDeviceNotifier = DeviceNotifier.OpenDeviceNotifier();
UsbDeviceFinder MyUsbFinder;
UsbDevice MyUsbDevice;
UsbEndpointReader EPReader;
UsbEndpointWriter EPWriter;
int bytesWritten;
public DateTime LastDataEventDate = DateTime.Now;
public Main_Form()
{
InitializeComponent();
Control.CheckForIllegalCrossThreadCalls = false;
UsbDeviceNotifier.OnDeviceNotify += OnDeviceNotifyEvent;
}
void OpenUSB(int VendorID, int ProductID)
{
toolStripStatusLabel.Text = "Opening USB";
MyUsbFinder = new UsbDeviceFinder(VendorID, ProductID);
MyUsbDevice = UsbDevice.OpenUsbDevice(MyUsbFinder);
if (MyUsbDevice == null) { USBConnection_label.Text = "USB Not Connected"; CloseUSB(); }
else
{
USBConnection_label.Text = "USB Connected";
USBInfo_label.Text = "VID = " + MyUsbDevice.Info.Descriptor.VendorID.ToString() +
", PID = " + MyUsbDevice.Info.Descriptor.ProductID.ToString();
IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice;
if (!ReferenceEquals(wholeUsbDevice, null))
{
wholeUsbDevice.SetConfiguration(1);
wholeUsbDevice.ClaimInterface(0);
}
EPReader = MyUsbDevice.OpenEndpointReader(ReadEndpointID.Ep01, 7);
EPWriter = MyUsbDevice.OpenEndpointWriter(WriteEndpointID.Ep01);
EPReader.DataReceived += OnUsbDataReceived;
EPReader.DataReceivedEnabled = true;
}
}
void WriteUSB(int Site)
{
toolStripStatusLabel.Text = "Writing Data...";
ErrorCode ECWriter = EPWriter.Write(Encoding.Default.GetBytes(Site.ToString()), 100, out bytesWritten);
if (ECWriter != ErrorCode.None) throw new Exception(UsbDevice.LastErrorString);
}
void CloseUSB()
{
toolStripStatusLabel.Text = "Closing USB";
if (MyUsbDevice != null)
{
if (MyUsbDevice.IsOpen)
{
IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice;
if (!ReferenceEquals(wholeUsbDevice, null))
{
wholeUsbDevice.ReleaseInterface(0);
}
MyUsbDevice.Close();
}
EPReader.DataReceived -= OnUsbDataReceived;
EPReader.DataReceivedEnabled = false;
EPReader.Dispose();
EPWriter.Dispose();
}
MyUsbDevice = null;
UsbDevice.Exit();
}
void OnDeviceNotifyEvent(object sender, DeviceNotifyEventArgs e)
{
toolStripStatusLabel.Text = "Device Notify Message: " + e.EventType.ToString();
if (e.EventType.ToString() == "DeviceRemoveComplete") { USBConnection_label.Text = "USB Disconnected"; CloseUSB(); }
else if (e.EventType.ToString() == "DeviceArrival") { USBConnection_label.Text = "USB Connected"; OpenUSB(4660, 1); }
}
void OnUsbDataReceived(object sender, EndpointDataEventArgs e)
{
toolStripStatusLabel.Text = "Receiving Data!!!";
byte[] s1stat = e.Buffer;
S1SOT_textBox.Text = s1stat[0].ToString();
S2SOT_textBox.Text = s1stat[1].ToString();
S1EOT_textBox.Text = s1stat[2].ToString();
S2EOT_textBox.Text = s1stat[3].ToString();
S1BIN_textBox.Text = s1stat[4].ToString();
S2BIN_textBox.Text = s1stat[5].ToString();
TowerLamp_textBox.Text = s1stat[6].ToString();
Time_label.Text = (DateTime.Now - LastDataEventDate).TotalMilliseconds.ToString();
LastDataEventDate = DateTime.Now;
}
private void Main_Form_FormClosing(object sender, FormClosingEventArgs e)
{
toolStripStatusLabel.Text = "Closing App";
CloseUSB();
}
private void Main_Form_Load(object sender, EventArgs e)
{
toolStripStatusLabel.Text = "Opening App";
OpenUSB(4660, 1);
}
private void Write_button_Click(object sender, EventArgs e)
{
CloseUSB();
OpenUSB(4660, 1);
WriteUSB(Write_comboBox.SelectedIndex+1);
}
}
}